OBJECTIVES: 1) To determine the diagnostic accuracy of the diagnostic program using this challenging data set. 2) To determine the inter-observer error with four readers examining the same data set. 3) To determine the most significant logic errors. 4) To learn how to correct for important diagnostic errors. 5) To develop the use of measurement selection techniques to determine the ordered strengths of 33 variables used for diagnostic purposes in bone disease. 6) To determine important errors in the technology of programming and using a computer for diagnostic purposes. 7) To determine whether the diagnosis obtained by a radiologist using a computer has been influenced by the diagnosis in his mind when he began the examination. 8) To expand the L-Bayes program to other diagnoses. 9) To continue the function of the Mid-America Registry for patient care and enlarging the data base. 10) To institute the development of new innovative approaches to computer diagnosis with emphasis on management first, and diagnosis second. 11) To consider new technologies for transfer of useful diagnostic programs.